COPD is the third leading cause of death and the leading cause of disability in the US. Despite the growing availability of efficacious pharmacotherapy for COPD, patients still experience a significant disease burden and with more than half reporting significant impairment in functioning. Thus the efficacy of COPD medications in clinical trials stands in stark contrast to the poor outcomes experienced by patients in the real world. One possible explanation for this gap is low rates of medication adherence. Only 25% of COPD patients are adherent, which is the lower than other chronic illnesses including diabetes, hypertension and congestive heart failure. Despite the high prevalence of nonadherence in COPD interventions there are significant gaps in the development and evaluation of interventions for adherence. Previous research has been based on cross sectional studies using self-reported measures of adherence and largely a theoretical. In the absence of data, many hospital systems are developing interventions to address medication adherence as part of their clinical program to reduce hospital readmissions and avoid financial penalties from CMS. This project proposes to recruit 360 patients with COPD to longitudinally evaluate potential determinants on adherence and disease progression based on theory of self-regulation. Participants will use novel electronic medication monitors to measure adherence to long term controller and rescue medications and ecological momentary assessments to measure patient reported respiratory symptoms and patients reactions including outcome expectancies, self-efficacy to management symptoms and medication health beliefs. This data will be used to evaluate the theory of self-regulation in COPD. Participants will also complete bi-annual clinical visits to track disease progression on clinical outcomes (e.g., lung function, functional status, quality of life) and psychological/ cognitive functioning. The impact f this study is to identify novel and potentially powerful targets for behavioral interventions in COPD which has been understudied despite its tremendous detrimental impact on overall public health.